1. Field of the Invention
This invention relates to lubrication of drive chains and in particular to those applications where lubrication is critical to the operation, but must be controlled to prevent contamination of materials near the drive chains.
2. Description of the Prior Art
Chain lubricators are commercially available in a variety of configurations ranging from a simple wick that transfers lubricant from a reservoir to the chain through capillary action to an elaborate system that injects lubricant under pressure at pre-determined intervals of time. All of these lubrication methods share a common property of delivering a fixed amount of lubricant over a unit of time. If underlubrication or overlubrication occurs, the rate of delivery can be adjusted manually after the condition is discovered. Many times, however, the condition which warrants manual adjustment is discovered too late and chain damage or environment contamination has already occurred.
3. Brief Description of The Invention
An important object of the present invention is to provide a simple inexpensive but positive lubrication system for properly lubricating a chain drive by sensing friction conditions in the tension side of the chain run and supplying lubricant into the non-tension side of the chain run where the lubricant is most easily picked up in the chain components that are subject to wear.
A further important object of this invention is to obtain satisfactory lubrication in a chain by a unique mechanism which senses sliding friction between the chain and friction sensing means which determines by a predetermined movement whether to dispense more lubricant or withhold the dispensing of lubricant, thereby relying on the ability to translate the sliding friction response into a truly automatic chain lubricator.
A preferred embodiment of the present invention resides in the lubrication control as applied to a driven endless chain that passes the chain from the tension run to the non-tension run, and in which a control is responsive to friction responsive means associated with the tension side of the chain so that the friction condition between the chain and the friction responsive sensing means is able to determine when dispensing a supply of a lubricant for the chain is to occur, such as in response to a predetermined friction level by dispensing lubricant onto the non-tension side of the chain so as to reduce the friction in the chain pins and bushings, or other parts, while preventing the release of excessive quantities of lubricant.
A further embodiment of a chain lubricator system comprises arranging chain guiding channels for supporting the chain in its tension driving run and in its non-tension return run, constantly monitoring the condition of the friction between the chain run through a movable section of the guide channel to determine when to deliver lubricant, as well as the frequency of delivery into the guide channel on the non-tension run of the chain, thereby reducing the amount of friction in the system between the chain and the guide channel.
Where previous lubricators depend on manual adjustment and feedback adjustment in order to perform satisfactorily, this invention employs the sensing of sliding friction between the chain and a friction sensing device that moves in response to friction in order to determine whether to dispense more lubricant or not. While not only eliminating the manual adjusting and readjustment, this invention senses the friction conditions on a continuous basis to make it a truly automatic lubricator. The problem heretofore encountered in connection with chain drives of various guides has been the lack of proper lubrication on a basis that avoids the extremes of too little lubrication or too much lubrication. That problem is overcome by the present invention in regulating the supply of lubrication while the chain is in operation, and providing assurances that while the chain is not operating, lubrication will not be supplied.